1. Field of the Invention
The present invention relates to the hanger mechanism for the attachment of a soil engaging tool to a tool bar. More particularly, the present invention relates to a hanger mechanism which utilizes two parallel arm structures pivotally interconnected to other structures and allows the soil engaging tool to move only in a substantially vertical direction as the soil engaging tool moves over changes in the contour of the soil surface.
2. Description of the Prior Art
In various farming operations such as planting and plowing, it is well known that it is desireable to maintain a soil engaging tool at a uniform depth within the soil.
A type of hanger mechanism typical of those known in the prior art has a single arm which extends rearward (with reference to the tractor) from a tool bar and is pivotally attached to the tool bar. The soil engaging tool is attached at the rearward end of the arm. A pressure rod which is provided with a compression spring could be attached between the tool bar and the soil engaging tool (or at said opposite end of the single arm) in an attempt to maintain the soil engaging tool at a constant depth. This construction will substantially vary the depth of the soil engaging tool (unless there is an extremely long radius) because the soil engaging tool will not move in a substantially vertical direction. The soil engaging tool will move about an arc whose radius is the distance between said tool and the tool bar. Thus, as the soil engaging tool is urged upward and downward, it moves about an arc and its angular relationship with the vertical changes which will alter the depth of the soil engaging tool within the soil.
This prior construction, in order to allow the soil engaging tool to move substantially vertically, would have to extend rearward (with reference to the tractor) from the tool bar a considerable distance. The extension of the hanger mechanism would prevent or make difficult the transporting or folding of the agricultural vehicle if desired.